honestly I think you're overthinking this. Yeah every word in the language can be interpreted or misinterpreted. I think it's pretty clear that remote work is a thing, acceptable, and encouraged.
on the face of it, it doesn't sound like egregious abuse of the system, this last year there were many reports of similar encounters when arriving in Bangkok, whereas entries into CNX forinstance went smoothly.
Seems they might be wising up, eluding to the category the visa was obtained under. Possibly extensions will need to provide same category proof or a new category 10,000 baht DTV application/extension fee may apply.